1. Field of the Invention
The present invention relates to a process for preparing a malonic monoester which is useful as an intermediate in the production of medicines or agricultural chemicals.
2. Description of the Related Art
Hitherto, a malonic monoester has been prepared by
(1) partially hydrolyzing a malonate diester which is prepared from malonic acid (see Org. Synthesis Coll., 4, 417 (1963)),
(2) partially hydrolyzing di-tert.-butyl malonate which is prepared from diethyl malonate (see Carbohydr. Res., 169, 171 (1987)),
(3) partially hydrolyzing di-tert.-butyl malonate which is prepared from malonic acid (see Rec. Trav. Chim., 58, 1048 (1939)), or
(4) reacting tert.-butylisocyanide with malonic acid and an alcohol (see J. Chem. Res., 119 (1977)).
All of these processes have drawbacks such as requirement of multistep reactions, low yields or the use expensive reagents, and are not suitable as technical processes for the preparation of a malonic monoester.